Tooth trail to mammal ancestor

New Delhi, Nov. 8: Indian scientists have discovered the earliest known ancestor of hoofed mammals near Kisalpuri in Madhya Pradesh, using a single fossil tooth to describe an extinct species.

The lower molar belonged to a creature that lived about 66 million years ago and represents the world’s oldest hoofed mammal, palaeontologists from Panjab University and Jammu University announced today.

The tooth of this mammal has features associated with grinding and crushing which are also found in other archaic, extinct hoofed mammals, the researchers said. Their findings will appear in the US journal Science tomorrow.

The five-member Indian team has named the mammal Kharmerungulatum vanvaleni, after the Kharmer river nearby.

Ungulates, or hoofed mammals, today represent the greatest diversity among herbivores and include antelopes, cows, horses, goats and rhinos, among others. Until the tooth turned up in Kisalpuri, the oldest known ungulate mammals were known from 63 million-year-old rocks from north-east Montana in the US.

“The Indian tooth is about three million years older and represents the oldest archaic ungulate so far anywhere in the world,” team member Guntupalli Prasad from Jammu University told The Telegraph.

“Archaic ungulates had evolved a tooth structure that was suitable for grinding and crushing herbivorous diets in contrast to teeth adopted for carnivorous diets among other mammals of the time,” Prasad said.

The discovery of the oldest hoofed mammal in India has implications for the origin, diversification and the evolution of these mammals across the continents. Although fossils of ancestral hoofed mammals have been previously described from North America, South America and Europe, none is from periods beyond63 million years.

“This is the first record of a hoofed mammal from the era of dinosaurs,” said Ashok Sahni, a senior palaeontologist and team member from Panjab University, Chandigarh. “This discovery raises the possibility that the earliest hoofed mammals evolved in India when the subcontinent was an island, drifting towards Asia,” Sahni said.

The researchers believe Kharmerungulatum vanvaleni was a primitive, rodent-sized creature. The scientists used the 2mm tooth to estimate the jaw size, from which they estimated the size of its skull and the size of the body.

The tooth was found in a collection of 50 teeth and bone fragments recovered from sediments beneath volcanic rocks near Kisalpuri, a village in Madhya Pradesh. Fossils of dinosaur eggs, fish, lizards and turtles were also abundant in the sediments.